Byul shares how HaHa got jealous over Sung Si Kyung

On March 18, Byul appeared on MBC FM4U's 'Kim Shin Young's Hope Song at Noon' as the special DJ.

During the radio show, one listener requested a song by Sung Si Kyung. After hearing his song, Byul commented, "He has many emotional songs."The DJs then talked about Sung Si Kyung, and Byul shared, "My husband is very conscious of Sung Si Kyung."

She explained,"On some show, I said I want to do a duet with Si Kyung oppa, and he asked me why I'm calling him 'Si Kyung oppa.' I explained he's an oppa since he's a sunbae and older than me. My husband then told me to just call him Sung Si Kyung (without the oppa)."